Power amplifiers are non-linear devices that cause distortion to the amplified signal. An amplifier maintains a constant gain (the ratio of output to input power or amplitude) for low-level input signals. However, at higher input levels, the amplifier goes into saturation and its gain decreases. Moreover, signal distortion increases during saturation.
The power amplifiers may be operated at a constant gain (or linear portion) to reduce distortion. However, the operation in the linear portion of the amplifier does not allow the amplifier to amplify the input signal to its full potential. Moreover, operation of the amplifier in the linear portion utilizes high levels of energy.
Linearization of the power amplifier is often utilized to overcome the non-linearity of the power amplifier. Linearization may accomplished by various digital pre-distortion techniques. However, conventional methods of digital pre-distortion are limited by the bandwidth of the input signal. For instance, electrical components (e.g., Analog-to-Digital converters (ADCs)) that facilitate in the digital pre-distortion are only able process signals up to a maximum bandwidth. Accordingly, the linearization and signal amplification is negatively affected when the signal bandwidth (including distortion) is greater than the maximum bandwidth.
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